XML 48 R36.htm IDEA: XBRL DOCUMENT
v3.19.2

Investments - Maturity Table (Details) - USD ($) $ in Thousands | Jun. 30, 2019 | Dec. 31, 2018
--- | --- | ---
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | $ 331,519 | $ 182,325
Available-for-sale investments | 331,541 | $ 176,245
2020 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 39,484 |
Available-for-sale investments | 39,545 |
2021 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 37,689 |
Available-for-sale investments | 37,787 |
2038 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 262 |
Available-for-sale investments | 282 |
2039 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 2,907 |
Available-for-sale investments | 3,065 |
2042 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 8,021 |
Available-for-sale investments | 7,800 |
2043 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 13,727 |
Available-for-sale investments | 13,776 |
2044 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 20,078 |
Available-for-sale investments | 20,090 |
2045 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 22,915 |
Available-for-sale investments | 22,728 |
2046 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 35,609 |
Available-for-sale investments | 35,195 |
2047 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 53,183 |
Available-for-sale investments | 52,759 |
2048 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 15,159 |
Available-for-sale investments | 15,511 |
2049 |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 82,485 |
Available-for-sale investments | $ 83,003 |

X
- Definition Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=118942338&loc=SL82898722-210454 + Details
Name: | us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=118942338&loc=SL82898722-210454 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118954083&loc=d3e26610-111562 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2020Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2021Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2038Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2039Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2042Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2043Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2044Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2045Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2046Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2047Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2048Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=slm_Maturity2049Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |